Sofa



FIG. 1 is a front view of the sofa;

FIG. 2 is a top view of the sofa;

FIG. 3 is a bottom view of the sofa;

FIG. 4 is a back view of the sofa; and,

FIG. 5 is a right side view of the sofa.

The ornamental design for a sofa, as shown and described.